Modulated optical carriers (optical signals) are used to convey information signals such as voice and data signals. An optical signal typically passes through a number of switching nodes in the course of its journey between a source user device and a destination user device. The switching nodes selectively, and often transiently, connect one of many source user devices to one of many destination user devices for the purpose of routing an optical signal between the user devices. Conventionally, the optical signal is switched electrically at each switching node. The optical signal is converted to an electrical signal, routing information included in the electrical signal is read, the electrical signal is routed to a destination port connected to the next switching node determined from the routing information. Then, at the destination port, the electrical signal is converted back to an optical signal that is transmitted to the next node. The conversion process just described reduces the rate at which the information represented by the information signal can be conveyed through the network.
Some optical networks include a supervisory channel. An optical signal transmitted through the supervisory channel is converted at the nodes of the network to electrical signals that configure the network to establish a transmission path between two user devices. Once the network is configured, optical signals can then be transmitted directly between the user devices. However, the need to convert the optical supervisory signals to electrical signals is expensive and reduces the rate at which the configuration of the network can be changed. This is especially problematical in a network that employs packet switching.
Thus, what is needed is a way to increase the rate at which the configuration of the i optical network can be changed.